6.6 seconds is considered below average for a 40 yard dash for a 12 year old boy. To improve this I would just practice sprints and do leg workouts such as squats.
A 10 yard dash time is really not a good judge of your speed, the distance is too short. A 40 yard dash is what you need to get a good estimate of your abilities. but I'll give you time for both 40 yard dash-between 5-5.8 seconds 10 yard dash-between 1.3-1.5 seconds
14 seconds
superman-.00000001
A 12.5-second 100m equates to a time of 4.572 seconds in the 40-yard dash.
Jake Plummer's 40 yard dash time is 4.76 seconds. He is in the Air Force.
His time at the combine prior to his rookie season was a 4.64 seconds 40 yard dash.
4.5 seconds or lower
Walter Payton 40 yard dash time was 3.90 seconds.
Walter Payton 40 yard dash time was 3.90 seconds.
Usain bolt runs his 40 yard dash in around 4.2 seconds.
4.75 seconds
4.77 seconds